Ball type flexible coupling for rigid conduits

ABSTRACT

A coupling designed to provide a pressure tight connection between a pair of rigid tubular conduits despite misalignment. The coupling includes cylindrical sealing surfaces as well as mating spherical surfaces, one integral with or secured to the conduit and the second being a part of the coupling housing. The disclosure shows the use of conventional 0 ring type seals positioned between cylindrical sealing surfaces. The centers of the spherical surfaces are located at the axis of the conduit and aligned with the seal portion so that relative movement of the conduit with respect to the coupling also produces longitudinal movement of the conduit and minimal compressive loading of the 0 ring seal. An arrangement of coupling parts employing split or C ring parts and cooperating wedge ring is disclosed to provide noncaptive mounting parts.

United States Patent 1 3,695,644 Goldberg [451 Oct. 3, 1972 BALL TYPEFLEXIBLE COUPLING 858,049 12/1952 Germany ..285/261 FOR RIGID CONDUITS537,764 5/1955 Belgium ..285/261 [72] Inventor: Leonard z. Goldberg,Canoga Park, 1,084,987 v 7/1960 Germany ..285/233 Cahf' PrimaryExaminerThomas F. Callaghan [73] Assignee: Lockheed AircraftCorporation, Attorney-Lowell G. Turner and George C. Sullivan Burbank,Calif. [22] Filed: March 30, 1970 E5 d d h coupling esigne to provi e apressure tig t con- [21] Appl' 23,811 nection between a pair of rigidtubular conduits despite misalignment. The coupling includes cylindri-52 US. Cl ..285/233, 285/166 Cal Sealing Surfaces as as mating Spherical51 Int. Cl ..Fl6l 27/04 faces One integral with Secured the and [58]Field of Search 285/166 233 261 the second being a part of the couplinghousing. The disclosure shows the use of conventional 0 ring type sealspositioned between cylindrical sealing surfaces. [56] References CltedThe centers of the spherical surfaces are located at the UNITED STATESPATENTS axis of the conduit and aligned with the seal portion so thatrelative movement of the conduit with respect to 2,852,282 9/1958 Sm1sk0et al ..285/ 166 X the coupling also produces longitudinal movement fTorres the conduit and compressive loading of the 0 3,052,491 9/1962Grass ..285/233 ring seal. 2,329,369 9/1943 Haver ..285/166 X 2 286 5666/1942 Norton ..285/261 x arrangement Pans emplymg C ring parts andcooperating wedge ring is disclosed to FOREIGN PATENTS OR APPLICATIONSprovide noncaptive mounting P 881,504 l/1943 France ..285/166 3 Claims,9 Drawing Figures PATENTEDHBT3 m2 3,695,644

sum 1 or 2 v Q mm m.

INVENTOR. LEONARD Z. GOLDBERG B3) 0 kfvflwd Agents PAIENTEDUBIEI I972 395 4 SHEET 2 BF 2 I, v." "I. r

INVENTOR. Y LEONARD Z. GOLDBERG BALL TYPE FLEXIBLE COUPLING FOR RIGIDCONDUITS BACKGROUND OF THE INVENTION The need for improved couplings forrigid conduits has long been recognized. One of the most criticalrequirements is to allow for angular or translation misalignment or insome cases relative movement of the conduits without loss of pressure orfluid. In the past, many couplings have been designed employing matingspherical surfaces in the conduit and seal to allow angular movement.These couplings have assumed complex forms and invariably have requiredsealing of the spherical surfaces.

BRIEF STATEMENT OF THE INVENTION I have produced a spherical couplingwhich exhibits an ability to accept conduit misalignment or movementemploying a minimum number of seals and no seals in the sphericalregions. Furthermore, simple ring seals are used and so positioned thatthey are primarily loaded in compression for effective sealing.

Basically, the invention employs a ferrule having a cylindrical portionand a spherical portion. A body member includes a spherical portion anda cylindrical seal retaining portion. A seal is retained and compressedbetween the cylindrical portions of the body and ferrule.

In one embodiment, the seal employs a split ring spherical portion and aseparable continuous wedge ring which cooperate to provide a sphericalbearing surface with hoop strength and positioning provided by the wedgering.

In certain embodiments, the O ring or actual seal member is loaded onlyin compression transverse to the axis in the conduit and in otherembodiments, the O ring is packed, that'is, axially loaded as well by acontrolled predetermined load.

DETAILED DESCRIPTION OF THE DRAWINGS This invention may be more clearlyunderstood by the following detailed description and by reference to thedrawing in which:

FIG. 1 is an elevational view partially in section of the coupling inaccordance with the principle of this invention;

FIG. 2 is a vertical section through a coupling of a type of FIG. 1shown mounted on conduits with approximately 16 of angular deviationbetween the conduit;

FIG. 3 is a vertical section through a half coupling incorporating theprinciple of this invention;

FIG. 4 is a fragmentary sectional view of a coupling incorporating theprinciple of this invention but employing a different type of lockingmember and seal;

FIG. 5 is a fragmentary sectional view of an alternate embodiment ofspherical surface attachment;

FIG. 6 is another alternate version of spherical surface attachment;

FIG. 7 is a fragmentary sectional view of an embodiment of thisinvention employing captive coupling parts;

FIG. 8 is an enlarged detail of the assembly of FIG. 1 showing therelationship between the split ring and the locking wedge ring; and,

FIG. 9 is an expanded view of the C ring of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION Now referring to FIG. 1, acoupling 10 employing this invention may be seen as including a firstbody portion 11 having a knurled hand grip region 12 and a threadedregion 13 which engages a second body portion or nut 14. Both the bodyportion 11 and the nut 14 include respective annular retainer portionsor lips 15 and 16 which position and retain split rings 17 and 18,respectively. The split rings 17 and 18 include respective hollowspherical surfaces 19 and 20 constituting segments of a sphere. Thesplit rings 17 and 18 also include cavities or relieved portions 21 and22, respectively, terminating in respective annular walls 23 and 24. Thewalls 23 and 24 constitute retainers for seal members 25 and 26 shown assimple conventional 0 rings. On the opposite or central side of the 0rings 25 and 26 is a common U cross-section back-up ring 27 axiallyaligned within the body portion 11 and having internally extending legs28 and 29, which may be directed radially inward, as shown, or reversedfor outward direction.

Positioned within the body and nut assembly are a pair of ferrulemembers 31 and 32 including internal cylindrical walls 33 and 34 andeach having an end lip or retainer 35 and 36. The cylindrical internalwall portions 33 and 34 are designed to match the outside diameter ofconduits intended to be secured and sealed together by the coupling ofthis invention. The end walls or lips 35 and 36 constitute stops tolimit the entrance of the conduits into the coupling. Theferrules aresecured to the respective conduit ends by welding, swaging or otherwell-known methods of attachment.

The ferrules 31 and 32 are characterized by spherical surfaces 37 and38, respectively, which engage the mating surfaces 19 and 20 of thesplit rings 17 and 18. The mating spherical surfaces have their centeron or near the center line C of the coupling and the mating surfaces aredimensioned for close slip fit. Sealing of the coupling and the entirejoint is accomplished not at the spherical surfaces but between the 0rings 25 and 26 and its contacted surfaces, principally the cylindricalsurface 41 and 42 and in the case of 0 rings 25 and 26, with thecylindrical surfaces 41 and 42 of their respective ferrules 31 and 32together with'the inside surface of body 1 1.

It is apparent from the above description of the coupling 10 of FIG. 1that the ferrule elements 31 and 32 include two distinct significantportions; namely, the spherical sections 37 and 38 and the cylindricalsections 41 and 42. The spherical sections 37 and 38 each have theircenter on or near the center line C, but more specifically at the originpoints 0-37 and O-38 on the plane normal to the axis C which passesthrough the seals 25 or 26. Referring specifically to the right end ofthe coupling of FIG. 1, any relative movement between the ferrule 31 andbody portion 11 results in movement of the cylindrical portion 41 in adirection generally normal to the axis C. Such movement in the normaldirection results in local compression or release of the loading on theO ring 25. The O ring 25 and cylindrical portion 41 form a static anddynamic seal with variable loading depending upon the misorientation ofthe ferrule (and its mating conduit with the coupling body portion 11).The same relationship occurs between the seal 26 and surface 42. Incontradiction to prior art spherical couplings, there is no seal actionon the spherical surfaces. The outside diameter of rings 25 and 26 arestatic with respect to the inside body surface and are dynamic withrespect to the annular portion of the ferrules. The mating sphericalsurfaces 19 and 37 and 20 and 38 constitute dirt and moisture barriers,and bearing surfaces to permit relative movement while axially loadedwith all pressure sealing between the interior and exterior. of theconduits performed by the O ring seals 25 and 26.

Now refer to FIG. 2 where a coupling similar to the one of FIG. 1 isshown in full section with tubes or con duits 49 and 50 shown in sectionand the entire coupling and conduits shown in a degree of angularmisalignment. In this and other figures, parts which are identical withmost parts of FIG. I carry the same reference numeral. In this case,referring to the right hand end of the assembly, the conduit 49 is showninserted into the coupling with its end resting against a step 51 in theend lip portion 53. The conduit 50 similarly rests against step 52in theend lip 54in ferrule 32. The conduit 49 is permanently secured to itsferrule 31, as by welding or swaging or other manners well known in theart.

In this figure, the tube 50 is shown displaced approximately 8 from theaxis of the conduit 49 and the relative movement between the matingspherical surfaces 19 and 37 associated with the conduit 49 and themating surfaces 20 and 38 are apparent. The body portion 1 l and nut 14include end openings 59 and 59a, respectively, to allow the sphericalsurfaces 37 and 38 to move in and out of the coupling withoutinterference.

In the drawing, ring 170, roughly comparable to ring 17 of FIG. 1, isusually split and manufactured separately from the body portion 11. Thisis possible since the mating surfaces 19 and 37 perform no actualscaling function and a split in one or more places is not objectionable.However, the ring 170 may be of continuous construction or be anintegral part of nut 14 or body 1 1 as shown in FIG. 7. Positioned atthe inner end of the ring 170 is a washer 171 defining one wall of theseal retainer recess, with the other wall formed by channelcross-section back-up ring 127 being of greater length than the back-upring 27 of FIG. 1. Washer 171 may also be integral with split ring as inFIG. 1. The length of the back-up rings 27 of FIG. 1 and 127 of thisfigure is determined by the extent of angulation for which the couplingis designed. The coupling of FIG. 1 is designed for approximately 8total angulation while the coupling of FIG. 2 accepts approximately16,of total angulation between the two conduits. It is apparent fromFIG. 2 that the angulation is limited as shown at A and B of the figurewhere the points A and B of the split ring members 170, and itscounterpart 180, engage the conduits at points D and E, respective- Fromexamination of FIGS. 1 and 2, it is apparent that the couplings of thisinvention are unrestrained in thedirection of misorientation. In FIG. 1,the two conduits are shown aligned (0 misalignment) and in FIG. 2 withmaximum angular misalignment (for example, 16). Because of theuniversality of both ends of the coupling, another form of misalignmentis readily accepted as well. Although not shown in the drawing, the twoconduits may be parallel but offset in any direction. The seal maintainsits integrity in thiscondition as well.

Relative movement of the conduits within the limit of misorientationdoes not break the seal and repeated cycling of the joint does notaffect its integrity.

One additional feature of this invention is apparent in FIG. 2 withreference as well to FIGS. 8 and -9. It is noted above that the rings170 and 180 are diametrically split and therefore removable from theferrules 31 and 32; The lips 15 and 16 of the body portions 11 and 14have sufficient inside diameter to clear the spherical surfaces 19 and20. Therefore, the split rings 17 and 18 and body portions 11 and 14 areremovable from the ferrule 30 and 31. There are no captive parts. Inorder to insure sufficient hoop strength for the coupling, the splitrings 17 and 18 have tapered outer surfaces adjacent to the lips 15 and16. Triangular cross-section wedge rings and 161 of high strengthmaterial such as 17 4 Stainless Steel (A.S.T.M. Standard) are held inthe wedge-shaped opening and absorb hoop loading of the conduit.Different wedge rings may be used for different pressure and temperatureapplications. The inside diameters of wedge rings 160 and 161 are alsoof sufficient size to clear the spherical portions 37 and 38. Therefore,the couplings may be completely disassembled from the conduits, leavingonly the ferrules 31 and 32 in place.

The details of the wedge ring 160 are more .clearly seen in FIG. 8overlying the split ring 170. This ring includes a pair of parts 170aand 170b shown in FIG. 9 as including a C ring 172 on part 170a whichengages a groove 173 in part l70b. The C ring 172 is shown in place inFIG. 8. Alternatively or additionally, the parts 170a and 170b aresometimes staked or otherwise fixed to one another, at location 1700 inmember 170a which engage and hold the C ring to member 170a. The ends of172 are chamfered to accommodate engagement.

One further feature of this invention is apparent by reference again toFIG. 2 wherein the center of the spherical surface 38 is at point 0,,lying on plane P normal to the axis of the conduit 50 which passesthrough the cylindrical surface 42. Therefore, with relative movementbetween the conduit and the coupling, the surface 42 varies veryslightly in radial distance from the center O thereby introducingvariable compression into the O ring 26. Some sliding movement betweenthe O ring and the surface 42 occurs in a region adjacent to the end ofthe conduit 50 remote from the spherical bearing surfaces 20 and 38. TheO ring seals between cylindrical surfaces at all times and is maintainedin sealing contact by the packing afforded by washer 124 and leg 128 offlanged ring 127. The packing is constant, as a function of the extentof tightening of nut 14 on body 11 and is not a function of angulationof the coupling or system tension. Because.

'plications over broad temperature ranges without impairing theintegrity of the union.

The same concept of this invention is usable not only in a doublecoupling of the type shown in FIGS. 1 and 2, but as a half couplingjoining a box or other manifold as shown in FIG. 3. In this case, theequipment includes a boss portion 60 having a threaded circular outletportion 61 which mates with nut 14 identical with that of FIGS. 1 and 2.The outlet portion 61 includes an integral seal retaining wall 62 and acylindrical wall portion 63 defining two walls of a seal recess designedto accept an O ring seal 26. Spherical mating surfaces and 38 define thesurface of rotation of the conduit 50 about center 0. The ferrule 32includes the sealing surface 42 similar to the embodiments of previousfigures.

In the case of the single ended coupling of FIG. 3, the conduit 50 maybe actually misaligned with the opening in the boss 60 by approximately8 without loss of seal or mechanical integrity. In this case, the bossincludes clearance regions 64 and 64a to allow movement of the ferrule32 and conduit 50 relative to the boss 60.

The foregoing descriptions all involve a seal using a threaded securingbody or nut. Other types of securing means are usable and areillustrated. For example, FIG. 4 shows a single ended or half couplingsimilar to that of FIG. 3. In this case, the coupling is secured by acommercially available V-Band coupling 69 which engages the outersurface of a pair of conical-faced surfaces 70 and 71. The annularsecuring means 69 performs the same function as the nut 14 without thenecessity of engaging threads. The annular face portions 70a and 71aneed not have a high degree of flatness for the coupling to work sinceno scaling function is performed in the region of their engagement.Instead, in this case, a commercially available seal 73 known as theOmni seal or an O ring appears in the seal recess on the boss 60 and thecylindrical surface 42 of ferrule 32. Similar to the preceedingembodiments, the surfaces 20 and 38 are mating spherical segments onrelative movement of conduit 50 with respect to the boss 60.

In each of the foregoing embodiments, the spherical surface is formedintegrally with the ferrule. This is not manditory and in FIGS. 5 and 6,two alternate arrangements are shown. In FIG. 5, the spherical surfacemember 120 is secured to the ferrule member 132 by a recessed machinescrew 133. In this configuration, the spherical surface member 120 maybe produced using conventional ball-forming production techniques.

In FIG. 6, the spherical surface member 121 is of sheet metal and spotor seam welded to the ferrule 132 at points 135 and 136. The sheet metalmember 121 is particularly designed for roll forming production.Therefore, it may be seen that the coupling of this invention isadaptable to different methods of production as well as differentapplications.

FIG. 7 is an example of a coupling of the same general type as in FIGS.1 and 2, but including captive parts (when the coupling is secured toconduits). In this embodiment, the ferrules 31 and 32 include acylindrical surface 41 and 42 as well as integral spherical surfaces 19and 20. Coupling body portions 111 and 114 are threadably engaged andeach includes as an integral part the hollow spherical surfaces 19 and20. The body part 111 includes a step 122 against which bears a washer123 to confine a packed O ring 25. A similar 0 ring 26 is confined by awasher 124 bearing against an end step 125 of sleeve portion 114a. The 0rings are confined by a shaped channel ring 27 similar to itscounterpart of FIG. 1.

Note in FIG. 7 that the body parts 111 and 114 may be backed off fromengagement but are prevented from removal from their respective ferrule31 and 32 by the lack of clearance with the spherical surfaces 37 and38. Since the washer 123 and 124 are separate members as compared withthe integral walls 23 and 24 of FIG. 1, the body parts may include theintegral spherical surfaces and yet be slidable away from the joint whendisengaged. The sealing portions of the coupling, 0 rings 25 and 26,ring 27 and washers 123 and 124 may be readily removed and replaced ifrequired when the coupling nut and body are moved back but stillremaining on the conduit as shown in FIG. 7. I

From the foregoing, it may be seen that I have invented a new couplingdesigned 'to accept major degrees of misalignment and angulation betweentwo conduits while providing effective low seal loading sealing of theconduits in low, intermediate or high pressure systems. Characteristicof my invention is the use of spherical bearing surfaces whichfacilitate the positioning of the coupling and conduit and separatecylindrical sealing surfaces so positioned to maintain effective sealingdespite movement of the coupling and conduit about the center of thecylindrical surfaces. The center cylindrical surface is located on theaxis of the coupling and in a plane which is normal to the axis andtraverses the cylindrical sealing surfaces. This also provides acoupling which will move when a relatively low force is applied to theconduit and will remain displaced when pressurized in a tension-typesystem.

The above-described embodiments and process is furnished as illustrativeof the principles of this invention and are not intended to define theonly embodiments possible in accordance with our teaching. Rather,protection under the United States Patent Law shall be afforded to usnot only to the specific embodiments shown but to those falling withinthe spirit and terms of the invention as defined by the followingclaims.

Iclaim:

l. A coupling for conduits comprising:

a body having an annular, internal, spherically configured section and acylindrical section extending from said spherical section;

a cylindrical member having a spherical segment adjacent one endthereof, said spherical segment being complementary to said sphericalsection of said body and in mating engagement therewith wherein theadjacent end of said member extends in spaced relationship to saidcylindrical section of said body;

seal means disposed between said cylindrical section of said body andsaid adjacent end of said member and in axial spaced relationship tosaid spherical segment, said seal means lying at least partially in aplane normal to the axis of the coupling and passing through the centerof a sphere defined by said spherical section, said seal means beingdisposed for movement with respect to said member and in sealingengagement therewith;

a circumferential wall extending inward in diametrically spacedrelationship to said adjacent end and in axially spaced relationship tosaid spherical segment of said member and disposed between saidspherical segment and one side of said seal means;

wherein the coupling includes a diametrically split ring member definingsaid spherical section of said body, said body and split ring memberdefine an annular groove and a continuous hoop load bearing ring isconfined in said groove overlying the split ring.

3. The combination in accordance with claim 2 wherein said hoop loadbearing ring and body have inside diameters greater than the maximumdiameter of the cylindrical member whereby the coupling may bedisassembled upon removal of the split ring.

1. A coupling for conduits comprising: a body having an annular,internal, spherically configured section and a cylindrical sectionextending from said spherical section; a cylindrical member having aspherical segment adjacent one end thereof, said spherical segment beingcomplementary to said spherical section of said body and in matingengagement therewith wherein the adjacent end of said member extends inspaced relationship to said cylindrical section of said body; seal meansdisposed between said cylindrical section of said body and said adjacentend of said member and in axial spaced relationship to said sphericalsegment, said seal means lying at least partially in a plane normal tothe axis of the coupling and passing through the center of a spheredefined by said spherical section, said seal means being disposed formovement with respect to said member and in sealing engagementtherewith; a circumferential wall extending inward in diametricallyspaced relationship to said adjacent end and in axially spacedrelationship to said spherical segment of said member and disposedbetween said spherical segment and one side of said seal means; wallmeans extending inwardly diametrically, said wall means beingindependent from and movable with respect to said body and incomplementary spaced relationship to said circumferential wall adjacentthe other side of said seal means to confine said seal in cooperationwith said circumferential wall; and means associated with saidcircumferential wall and said wall means to control the longitudinalaxial movement of said seal.
 2. The combination in accordance with claim1 wherein the coupling includes a diametrically split ring memberdefining said spherical section of said body, said body and split ringmember define an annular groove and a continuous hoop load bearing ringis confined in said groove overlying the split ring.
 3. The combinationin accordance with claim 2 wherein said hoop load bearing ring and bodyhave inside diameters greater than the maximum diameter of thecylindrical member whereby the coupling may be disassembled upon removalof the split ring.